Method of producing beryllium alloys



Patented Nov. 8,1938 1 PATENT orrlcr.

METHODOF PRODUCING BEBYLLIUM ALLOYS Menahem Merlub-Sobel, Cleveland,Ohio, as- Q signor to The Beryllium Corporation, New York, N. Y., acorporation of Delaware v No Drawing. Application November '1, 1934,

Serial No. 751,965

Claims.

metals-such as cobalt, nickel, iron, and ferrous alloys of varyingcomplexity. In addition to those 15 already mentioned, alloys ofberyllium with aluminum have been shown to be of great value,particularly where great lightness is desired in coniunction withrelatively good strength. Similarly silver beryllium alloys have greatvalue because of their resistance to tarnish.

Despite the technical advantages gained by the use of beryllium as aconstituentof various alloys,

commercialization of such alloys has been retarded by their high cost.This has been the inevitable result of the necessity for makingberyllium ailoys by simple alloying of the metallic'elements, the highcost of beryllium metal-a reflection of its high standing in theelectromotive series-its high melting point, and lesser difliculties,such as 80 ready oxidizability, lack of fluidity, etc. Any economicalutilization of beryllium in alloy form therefore necessitates the directformation of the alloys from cheap beryllium compounds instead of thepresent practice of alloying the elementary metals.

Many attempts to accomplish this end have been made; Electro-depositionof beryllium into molten cathodes of copper,iron, etc. I have been triedby numerous workers, but all with failure or 40' at best indifferentsuccess. Codeposition of beryllium and copper has been suggested;likewise depositing alternately beryllium and copper, but no practicalresults have been found attainable. More recently, it has been proposedto manufacture copper-beryllium alloys by beryllium forma-' tion in thepresence of molten copper as a collecting agent, but it has been theapplicants experience with this procedure, even before the publicationof such data, that inadequate results are obtained. ..In all probabilitythe same factor is here involved which acts to inhibit the formation ofberyllium-copper alloys in the attempted deposition of beryllium into amolten copper cathode. In the latter case,-it has been observed by .allworkers in this field that there is so low a tendency for alloying ofthe light metal into the bath of the heavy metal that comparativelylittle of the beryllium is captured. Even at temperatures as high as-1400 0., above the melting point of beryllium, and irrespective ofwhether partially alloyed copper or pure copper is used, no significantelectroalloying takes place. It is therefore quite evident that, just aswith a molten cathode, so a molten collecting bath will not be foundsatisfactory. Efforts to disperse molten copper by spraying, orbycolloidal action, have not succeeded, and I have therefore been led to aprocedure which, though reversing normal outlooks, has neverthelessproven very successful, 11', instead of raising the temperature of thealloying metal bath, as all previous experimenters have attempted, inorder to increase alloying activity, the initial temperature be reducedto below the melting point of copper, or other heavy metal employed, andif the solid copper be present in a condition to present large surfaces,alloying takes place readily and smoothly. Moreover, aswill be shownlater, it is possible to make such a process readily continuous,ther':byremoving one of the fatal drawbacks to economy in all berylliumoperations in the wherever copper is referred to herein, the other heavymetals mentioned are to be considered as included, slight modificationsin technique necessitated by different melting points, etc. being, ofcourse, necessary.

Even the presence of copper in relative massive but always u n-moltenform makes for readier alloying, but I prefer that the copper or othermetal is added in more finely divided form and well dispersed in one orboth of the reacting constituents. The term dispersed" is notherein'usedin the technical sense as employed in-colloid chemistry, but in the moregeneral sense of subdivision ranging from granular or filamentouscondition to the molecular subdivision of so- 25 past. It is to beunderstood that l lution and thorough admixture with the otherreactants. I prefer powdered metal; and this can be made quiteeconomically by aqueous electrolysis, or by reduction of the metallicoxides by'hydrogen, carbon monoxide, carbo etc. For example, ground millinexpensive raw material for reduction to fine copper powder of thedesired time. a My experiments indicate that the reduction of theberyllium compound in the presence of such dispersed copper, asindicated, takes place most readily when a halide, or a mixture ofhalides, of beryllium is reduced by a metal more electropositive thanberyllium. It is known that the relascale provides an excellent,

. presence of dispersed copper.

tive electropositivity of beryllium and other metals involved in thisprocess varies in accord ance with the compounds in which such metalsappear. It is, therefore, to be understood that the term electropositiveand terms of similar import refer to the characteristic as exhibited inthe case of the compounds in question. For example, beryllium chloridecan be reduced by means of metallic sodium, the reactions beinginitiated at about 500 C., or even lower, in the I prefer to carry outthis reaction in a fused medium, with agitation. By employing a fusedmedium I am able to secure good contact between the heavy metal and theberyll um compound so that wherever reduction of the beryllium compoundoccurs, by reason of. contact with the reducing metal, the nascentberyllium can immediately contact the heavy metal. The fused mediumserves not only as a diluent and means of transmitting heat anddispersing the beryllium compound, heavy metal and, in some cases, thereducing agent, but also as a dispersion medium for the alloy ofberyllium and heavy metal whereby to prevent any possible occlusion ofunreacted materials by the alloy. Any alkali halide or alkaline earthhalide or any mixture of one or more thereofis suitable as a reactionmedium; Thesecompounds are not miscible with the resulting alloys andtherefore permit ready separation by gravity of themolten alloy. Sodiumchloride, calcium chloride and sodium fluoride are particularly wellsuited for the purpose, as will appear. Many of the alkali and alkalineearth halides are impractical on account of their high cost, althoughtheoretically suitable. Still other substances may be used asdispersion'media. I have made no attempt to determine exhaustively thesubstances which can be used, but it may be stated generally that anysubstance, which is molten at the desired temperatures and is inert toor does not react harmfully with the reacting substances or products ofthe reaction and lends itself to ready separation after the reaction, issuitable. It is not necessary to use any dispersion medium in additionto the reactants since the beryllium compound itself maybe fused and actas a dispersion medium for the other materials. however, desirable tohave the dispersion medium since the beryllium compounds are apt tovolatilize excessively ii the -.temperature goes much above theirmelting points. In the case of a compound such as sodium berylliumfluoride, the sodium fluoride component may be regarded as thedispersion medium.

In the case of the reduction of beryllium chlo ride in the presence ofdispersed, solid copper by means of metallic sodium it is desirable touse fused sodium chloride as a dispersion medium. The double salt sodiumberyllium chloride (NazBeCh) is formed which greatly reduces thevolatility of the beryllium chloride. Thus while the boiling point ofberyllium chloride is about 475 C., the double salt remainssubstantially unvolatilized at 800 C.

As stated above, I reverse the trend of the art by going to lowerinstead of higher temperatures.

I am able to effect the alloying of beryllium with the heavy metalat-temperatures even below the melting point of the alloy, as well as attemperaturesbetweenthe melting points of the alloy and the heavy metalconstituent thereof. As a practical matter it is advantageous to startthe-reaction at a temperature well below the melting 75 P int of thealloy and allow the heat liberated NazBeFr or the monofiuoride, BeFz.

be carried out with copper or other heavy metal maintained.

It is. 7

at altemperature below the melting point of the.

beryllium-heavy metal alloy. If such procedure is followed, thetemperature should be raised, after the reaction is complete, to a pointabove the melting point of the alloy,- in order to fuse and coalesce theparticles thereof.

Equally successful is the use of fluorides of beryllium, either thedouble fluorides such as This may in a dispersion medium consisting ofsodium fluoride, sodium chloride, calcium chloride or other alkali oralkaline earth halide, or, as previously shown, without any additionaldispersion jmedium. If sodium fluoride is employed with berylliumfluoride, the double salt is formed as in the case of the chlorides andwith similar advantage. These compounds can be reduced with sodium,calcium, or even magnesium. In the last-men tioned case, a ternary alloyis formed; and this has direct advantages of its own even over thebinary beryllium-heavy metal alloy. However, if only the binary alloy isdesired, the ternary may subsequently be held above the boiling point ofmagnesium for a time sufiicient to volatilize out that metal and retainonly the binary alloy.

Afurther modification of my invention permits the union of the reducingmetal with the alloyby the reaction to carry the temperature therea ingmetal, the basic principle of dispersion being For example, a fluorideof the above-mentioned type may be reduced by a copper-calcium alloy.Using an alloy of 40% calicum content will yield, after reaction, analloy of approximately 12- 15% beryllium, ideal as a master alloy fordilution with further copper to the 2-3% beryllium contentwhich iscommercially most desirable.

The same principle is ready applicable, to create a silver-berylliumalloy, by reducing beryllium chloride (preferably in combination withsodium chloride) by a sodium-silver alloy.

It is manifest that the readiness of alloying, in light of what I haveshown above, will vary with the particle size of the alloying metal andthat fair results may be had from the use of a relatively coarsedispersion of the heavy metal;

practical considerations, however, dictate that the heavy metal addedfor alloying be in a condition to measure no more than approximately OJof an inch each in at least two of its dimensions, and preferably in allthree. As already stated, I prefer truly powdered metal; and ranges of50 mesh to 200 mesh have proven eminently satisfactory for the'purpose'.However, a state of subdivision less fine may be successfully used,particularly where vigorous agitation is employed.

The process, unlike any hitherto in actual practice for beryllium or itsalloys, can be made fully continuous. For example, beryllium fluoride.made best by decomposition of the double ammonium beryllium fluoride,either in situ or separately, is added-continuously to a bath of sodiumfluoride or related fluorides, and simultaneously, there is continuousaddition of copper powder and of the reducing metal, sodium. The bath ispreferably held at a temperature above the melting point of thecopper-beryllium alloy to be made, and below the melting point ofcopper. As excesssodium fiuoride forms'in the bath, it can bebled'offand a continuous-flow of copper-beryllium alloy can be tapped from thebottom of the reaction receptacle. The same process is possible usingberyllium chloride and sodium chloride.

,It should be noted that it is possible to hold the bath itself at atemperature above the melting point of the heavy metal, provided suchmetal is contacted with the nascent beryllium before the particles ofheavy metal can melt and coalesce. I therefore wish it understood thatwhere bath temperatures are herein specified as below the melting pointof the heavy metal, such expressions are not to be strictly construedbut are to be given sufficient scope to cover such possible variations,within the spirit of my invention.

The process holds particular advantages over 1 the present standardprocedures; for alloying corrosive properties, of

beryllium with iron, nickel and even copper by reason of the possibilityof working at temperatures lower than the melting points of thesemetals, temperatures at'a suitable working range above the meltingpoints of these metals being undesirably high and difficult to control.

The percentage of beryllium in the alloy can readily be regulated byproportioning the beryllium compound and the reducing agent in relationto the other metal present. his generally convenient to produce thealloy with higher percentages of beryllium than is intended to be usedin the final product and then to dilute the alloy thus obtained bymelting it with a suitable additional'quantity of the other metal.

Examples (1) One hundred thirty parts by weight of maintained at thedesired low temperature by loss of heat to the surroundings, which canbe determined either by the construction of the equipment or by the rateat which'the sodium is added-or partly by each. Preferably the.temperature is kept below the melting point of the alloy produced butmay be between that tem-' perature (which varies according to thecomposition of the alloy) and the melting point of copper.

.After the reaction is complete, the temperature is raised to about1100" C. whereby to form a homogeneous alloy of beryllium and copperwhich is about five percent beryllium and to'volatilize any' excesssodium present. The temperature may optionally be kept down by theaddition during the latter part of the reaction of a further quantity offrom one hundred to two hundred parts by weight of copper either inpowder or granular or even relatively massive form whereby to give anend product of from two to three percent beryllium, the temperaturebeing raised after the reaction is complete to about 1100 C. to give ahomogeneous product.

(2) Eighty parts by weight beryllium chloride are brought to fusiontemperature. One hundred seventy five parts of copper powder are addedwith agitation. Continuing the agitation, fifty parts by weight ofmetallic sodium are added piecemeal and sufficiently slowly to avoid arise in temperature to a point above the melting point of copper beforethe reaction is substantially complete.

(3) One hundred thirty parts by weight of sodium beryllium fluoride areintroduced into a fused bath of sodium fluoride or sodium chloride andone hundred ten parts by weight of copper calcium alloy in powder formand containing i forty percent calcium, are added, with agitation,

and piecemeal. In this case the other conditions and procedure are theample. The copper-calcium alloy can be handledmore readilythan sodiumand contains the necessary copper. This procedure therefore possessessome advantages.

In both the above examples eighty parts of beryllium chloride can besubstituted for the sodium beryllium fluoride. The examples givenindicate desirable procedures, but, obviously, a great many variationsas to quantity, temperature etc. are possible and numerous selections ofreacting materials and end products can be made, all within the spiritand scope of my invention. I therefore wish it understood that I same asin the first exam limited only in accordance with the appended claimsand the prior art.

Having thus described my claim is:

1. Process of alloying beryllium with another metal which. alloystherewith comprising dispersing a reducible beryllium compound and suchother metal in finely divided solid form in a fused dispersion medium ata temperature below the melting point of such other metal and contactingthe dispersed substances with a reinvention, what I ducing agent for theberyllium compound.

whereby to cause contact of the nascent beryllium with the smallparticles of said other metal, the temperature, however, beingsufficient to effect said alloying.

' 2. Process of alloyingberyllium with one or more metals selected fromthe group consisting of copper, iron, nickel, cobalt and silver,comprising dispersing a beryllium halogen compound and said form, in afused dispersion medium selected metal or metals in finely divided fromthe group consisting of the alkali and alkaline earth halides andmixtures thereof, at a temperature below the melting point of said.

metal or metals but sufficient to efifect the alloying, and adding aberyllium reducing agent.

3. Process of alloying beryllium with another ,metal which alloystherewith comprising dispersing a reducible berylliumcompound and suchother metal, the latter being in finely divided solid form, in a fuseddispersion medium immiscible with the resulting alloy, at a temperaturebelow the melting'point of such other metal and contacting the dispersedsubstances with a reducing agent for the beryllium compound whereby tocause contact of the nascent beryllium with the small particles of saidother metal, the temperature being suflicient to effect the alloying.

4. The process offorming' beryllium-copper alloys comprising reacting aberyllium halogen compound with a metal more electropositive thanberyllium in the presence of finely divided solid copper.

below the melting point of said alloyable metal but sufficient to effectthe alloying.

7. The process of forming beryllium-copper" alloys comprising reacting aberyllium halogen compound with a reducing metal in the presence 'offinely divided solid copper.

8. The process of forming beryllium-copper alloys comprising. reactingsodium beryllium fluoride with magnesium in the presence of finelydivided solid copper. v

9. The process of forming beryllium-copper alloys comprising reactingberyllium chloride with metallic sodium in the presence of finelydivided solid copper. I

10. The process of forming beryllium-copper alloys comprising reacting aberyllium halogen compound with a metal more electropositive thanberyllium in the presence of finely divided solid copper, thetemperature of the reaction being maintained below the melting point oi.the copper. v

11. The process of forming beryllium-copper alloys comprising reacting aberyllium halogen compound with a metal 1 more electropositive thanberyllium inthe presence of finely divided solid copper, the temperatureof the reaction being maintained below the melting point of the copperuntil the reaction is substantially complete when the temperature israised to precipitate the alloy.

12. The process 01 forming. beryllium-copper alloys comprising reactinga beryllium halogen compound with a metal more electropositive thanberyllium in the presence of finely divided solid copper, thetemperature of the reaction being maintained below the melting point orthe copper and preferably close to the melting point 01' the alloy.

13. The process of forming beryllium-copper alloys comprising reacting aberyllium halogen compound with a metal more electropositive thanberyllium in the presence of finely divided solid copper, starting thereaction well below the melting, point of the alloy, and allowing thetemperature to rise above the melting point of the alloy and thenelevating the temperature above that of the copper.

14. The process 0f-.Icrming beryllium-copper alloys comprising reactinga beryllium halogen compound with a, metal more electropositive thanberyllium in the presence oi. finely divided solid copper, starting thereaction well below the melting point of the alloy, allowing thetemperature to rise above the melting point of the alloy and thenelevating the temperature above that of the copper, and addingadditional solid copper in a suitable state of division.

15. The process 01' forming beryllium-copper alloys comprising reactinga beryllium halogen compound with a metal more electropositive thanberyllium in the presence of finely divided solid copper, and addingadditional solid copper in divided state after the reaction is complete.

mam mun-scam.

